[NFC][MC][MSP430] Rearrange decoder functions for MSP430 disassembler (#155011)

Rearrange decode functions to be before including the generated
disassembler code and eliminate forward declarations.

Author: jurahul

llvm/lib/Target/MSP430/Disassembler/MSP430Disassembler.cpp

@@ -102,15 +102,6 @@ static DecodeStatus DecodeGR16RegisterClass(MCInst &MI, uint64_t RegNo,
   return MCDisassembler::Success;
 }
 
-static DecodeStatus DecodeCGImm(MCInst &MI, uint64_t Bits, uint64_t Address,
-                                const MCDisassembler *Decoder);
-
-static DecodeStatus DecodeMemOperand(MCInst &MI, uint64_t Bits,
-                                     uint64_t Address,
-                                     const MCDisassembler *Decoder);
-
-#include "MSP430GenDisassemblerTables.inc"
-
 static DecodeStatus DecodeCGImm(MCInst &MI, uint64_t Bits, uint64_t Address,
                                 const MCDisassembler *Decoder) {
   int64_t Imm;
@@ -142,6 +133,8 @@ static DecodeStatus DecodeMemOperand(MCInst &MI, uint64_t Bits,
   return MCDisassembler::Success;
 }
 
+#include "MSP430GenDisassemblerTables.inc"
+
 enum AddrMode {
   amInvalid = 0,
   amRegister,